The present invention relates to a fluid flow control apparatus, shifting tool and method and, more particularly, to a system, tool and method for controlling the flow of fluid in oil and gas earth wells utilizing reeled tubing.
Sliding sleeve valve assemblies are frequently used to control fluid between flow conductors, such as well tubing, and underground hydrocarbon producing formations. The sliding sleeve valve assemblies may be used to allow formation fluids to flow from an underground formation into a well tubing string and then to the well surface and/or to control the flow of stimulation fluids from the well surface to the underground formation, via the well tubing.
The valve assembly includes a sliding sleeve valve which is movable between an open position for permitting the flow of the stimulation fluid or the formation fluid to and from the formulation, and a closed position for preventing this flow. Known techniques of this type employ a shifting tool connected to wireline for opening and closing the sleeve valve, and threaded tubing for selective conveying the stimulation fluid from the well surface, through the sleeve valve and to the formation. However, these shifting tools, by virtue of being connected to wireline, rely on gravity for their operation. Thus, they are inadequate in connection with highly deviated and horizontal well completions.
Reeled tubing has been used in connection with well tools of the above type since the reeled tubing does not rely on gravity but rather can traverse highly deviated, or horizontal, wells which could otherwise not be traversed with wireline in a controlled manner. Also, since the reeled tubing is continuous, it can be more rapidly inserted into the well and can be more easily passed through downhole equipment. Reeled tubing can also be used to convey fluids to the well tubing, such as water, foam, paraffin, corrosion inhibitors, spotting acid, cement, and the like, for performing various functions including washing and cleaning the well tubing.
Since stimulation techniques are often necessary in deviated, or horizontal wells, there is a need to apply the advantages of reeled tubing with shifting tools for operating sliding sleeve valve assemblies in these types of wells.